fix: Add quay.io prefix, since docker hub image is obsolete

[bcopy]

Docker hub image is 7 months old and refers to inexistant ubuntu package repositories, failing the code example.

Description

Update the FROM image to the official upstream argocd image.

Checklist

Please make sure that your PR fulfills the following requirements:

• Reviewed the guidelines for contributing to this repository
• The commit message follows the Conventional Commits Guidelines.
• Tests for the changes have been updated
• Are you adding dependencies? If so, please run go mod tidy -compat=1.21 to ensure only the minimum is pulled in.
• Docs have been added / updated
• Optional. My organization is added to USERS.md.

Type of Change

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• New tests
• Build/CI related changes
• Documentation content changes
• Other (please describe)

Other information

[werne2j]

@bcopy please rebase and sign off on the commit when you have a chance

[bcopy]

@werne2j sorry, not sure what you mean by "sign off"

[bcopy]

I see one review approval is still needed